In municipal distribution systems, pipe are frequently interconnected so that the flow to a given outlet may come by several different paths.
As a result,we often cannot tell by inspection which way the flow travels,as in pipe BE.
The flow in any network,however complicated, must satisfy the basic relations of continuity and anergy as follows. This method called Hardy Cross Method
- The flow into any junction must equal the flow out of it.
- The flow in each pipe must satisfy the pipe friction laws for flow in a single pipe.
- The algebraic sum of the head losses around any closed loop must be zero
If the flow into and out of a two loop pipe system are shown below. Determine the flow in each pipe using only a basic scientific calculator. The k values of each pipe were given and n=2.
Solution
As a first step, assume a flow in pipe such that continuity holds at all junctions. Take clockwise flows as positive. Calculate deltaQ for each loop,make corrections to assume Qs. Repeat several times until the deltaQs are quite small.
cont.
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